docstr: Tests that the laplacian matrix rows and columns sum to zero.
docstr_tok: ["Tests","that","the","laplacian","matrix","rows","and","columns","sum","to","zero","."]
code: def test_build_matrices_laplacian_zero_rows_and_columns(
      self, size, channels
  ):
      """Tests that the laplacian matrix rows and columns sum to zero."""
      tensor_shape = np.random.randint(size, 6, size=3)
      image_init = np.random.uniform(
          0.0, 1.0, size=tensor_shape.tolist() + [channels]
      )
      image = tf.convert_to_tensor(value=image_init)
  
      laplacian, _ = matting.build_matrices(image, size=size)
      rows = tf.reduce_sum(input_tensor=laplacian, axis=-2)
      columns = tf.reduce_sum(input_tensor=laplacian, axis=-1)
  
      with self.subTest(name="rows"):
          self.assertAllClose(rows, tf.zeros_like(rows))
      with self.subTest(name="columns"):
          self.assertAllClose(columns, tf.zeros_like(columns))
  
imports: from absl.testing import parameterized
  import numpy
  import tensorflow
  from tensorflow_graphics.image import matting
  from tensorflow_graphics.util import asserts
  from tensorflow_graphics.util import shape
  from tensorflow_graphics.util import test_case
label_desc: Use image node_id 2 for calling the MattingTest obj's underlying member method code with example usage: obj.test_build_matrices_laplacian_zero_rows_and_columns(size, channels) without return types